// 引入 events 模块
var events = require("events");

// 创建 eventEmitter 对象
var eventEmitter=new events.EventEmitter();

// 创建事件处理程序
var handler=function connected(){
	console.log("conected ok")

	// 触发 data_received 事件 
	eventEmitter.emit("data_received");
}


// 绑定 connection 事件处理程序
eventEmitter.on("connection",handler);


eventEmitter.on('data_received', function(){
   console.log('数据接收成功。');
});


// 触发 connection 事件 
eventEmitter.emit("connection");
console.log("程序执行完毕")